Since thin film transistor liquid crystal display (TFT-LCD) has characteristics of small volume, low power consumption, no radiation and so on, it has become the leading products in the flat panel display market at present, wherein a TFT array substrate is the major component of the TFT-LCD.
A conventional TFT array substrate, as shown in FIG. 1, comprises: gate lines 19, data lines 20, and pixel units defined by the gate lines 19 and the data lines 20. Taking one of pixel units for example in FIG. 1, and at the same time referring to the sectional view of the pixel unit along the A-A line as shown in FIG. 2, it can be seen that the pixel unit comprises: a common electrode line 11, a gate electrode 13 of a thin film transistor, a source electrode 14 of the thin film transistor, a drain electrode 15 of the thin film transistor, a gate insulting layer 16, a semiconductor active layer, a passivation layer 17, a pixel electrode 12 and so on; wherein, the pixel electrode 12 is connected to the drain electrode 15 through a through-hole in the passivation layer between the passivation layer 17 and drain electrode 15.
As shown in FIG. 2, the gate insulating layer 16 and the passivation layer 17 are disposed between the common electrode line 11 and the pixel electrode 12, but when the through-hole in the passivation layer is fabricated by the conventional etching process, once the manufacturing error is presented, because the material of the passivation layer and the gate insulting layer is the same or similar to each other, the passivation layer will fracture, and it may also bring about the situation in which the gate insulating layer is eroded (for example, eroded by the etchant) and fractures in the same position. If this position is the location of the common electrode line, it will cause short circuit between the pixel electrode and the common electrode line, thus a bright spot or bright line may be presented on the liquid crystal display panel (display screen).